It is known to determine the location of a transmitting unit based on time of arrival differences or phase differences of a signal radiated by the unit at spatially separated receivers. Proposed techniques have included detecting a phase difference at respective receivers of a steady tone radiated by the unit, detecting a time difference of arrival for clock synchronized pulses radiated by the unit, and detecting a time difference of arrival of a common reference level of a randomly modulated signal. However, such techniques require that the transmitter radiate an additional signal comprising the required locating information, or that a complex, computationally intensive processing technique be used to recognize a common characteristic of a randomly modulated signal to identify a time delay of arrival. In addition, such techniques may require that signal samples be sent to a central processing unit for further processing to determine time difference of arrivals for the signals.